Liquid crystal display device and method of manufacturing liquid crystal display device

ABSTRACT

Provided is a liquid crystal display device including: a CF substrate; a TFT substrate disposed at a position facing the CF substrate; a transfer member provided at a corner portion in a bezel region of the TFT substrate; a spacer member for maintaining a distance between the CF substrate and the TFT substrate within a predetermined range; and a cutting mark made of the same material as that of the spacer member, and disposed on the CF substrate between a cutting line for the CF substrate from a mother CF substrate and the transfer member.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Divisional of U.S. patent application Ser.No. 14/223,993, filed on Mar. 24, 2014, which claims priority fromJapanese Patent Application No. 2013-065415 filed Mar. 27, 2013.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a technique for manufacturing liquidcrystal display devices with a slim bezel by surface close attachment.

2. Description of the Background Art

In most cases, when manufacturing liquid crystal display devices, aplurality of panels are provided on a single mother glass, and thendivided into individual panels. In recent years, in order to eliminategeneration of small scraps to simplify the manufacturing steps, and tomake efficient use of the mother glass, it has become increasinglycommon to manufacture liquid crystal display devices by closelyattaching adjacent panels (hereinafter referred to as “surface closeattachment”). Further, a bezel region constituting a non-display regionaround a panel tends to be made slim, and so-called bezel slimming hasbeen promoted.

In this manner, when panels are formed by surface close attachment andbezel slimming becomes advanced, a region for forming a transfer memberand a sealing member provided on a bezel region (for the sealing member,especially protrusions in which an inlet is provided) as well as amargin of distance for a cutting line for separating between panels andfor adjacent panels are reduced.

In addition, such a transfer member and a sealing member are bothtypically formed in such a manner that a paste material that has beenapplied is sandwiched between substrates and then spread therebetween,and therefore positions for formation and amounts of spread vary to arelatively large extent.

Therefore, it has become difficult to form a transfer member and asealing member in a predetermined region of formation for these memberswithout making their paste materials spread out of the region offormation. If the paste materials spread out over the cutting line forseparating between panels or over an adjacent panel region, the glasssubstrate may be adhered (bonded) by the paste material at a portion notdesired, resulting in wrong cutting.

As described above, in the case in which panels are formed by surfaceclose attachment and with a slimmer bezel, probability of a wrongcutting due to spreading of the paste materials increases, andconsequently it is difficult to manufacture liquid crystal displaydevices at a high yield ratio.

Thus, regarding the spreading out of paste materials, Japanese PatentApplication Laid-Open No. 2003-215622, International Publication No.WO00/45360, and Japanese Patent Application Laid-Open No. 2006-268020,for example, disclose a method of forming a transfer member a within apredetermined region by enclosing a region of formation for a transfermember and a sealing member by a sealing member or a columnar spacer ina form of a bank.

Further, Japanese Patent Application Laid-Open No. 2001-166121 disclosesprovision of a cutting mark as an indication of a position for cutting,near an intersection between cutting lines.

However, according to the method described in Japanese PatentApplication Laid-Open No. 2003-215622, when using the sealing member toform an enclosure for enclosing the transfer member, there is still aconcern that the sealing member as the bank itself may spread out, andas a result, it is not possible to provide the transfer member near acutting line, and a contribution of this method to bezel slimming is notthat much.

Further, according to the method described in International PublicationNo. WO00/45360, when using a columnar spacer to form a projection forenclosing both the sealing member and the transfer member, an enclosurein a form of the bank is to be additionally provided around the sealingmember only to prevent spreading out. Therefore, a region for forming anenclosure in a form of a bank itself increases, and a contribution ofthis method to bezel slimming is limited.

Moreover, according to the method described in Japanese PatentApplication Laid-Open No. 2006-268020, when forming the transfer memberand an enclosure using a columnar spacer for enclosing the transfermember inwardly from the sealing member for enclosing liquid crystals,there is a possibility that the transfer member is brought into contactwith the liquid crystals while it is possible to prevent an unnecessaryregion from increasing in the outside of the sealing member. Thisresults in a concern of a reduced yield ratio brought by factors such asdisplay defects due to contamination of the liquid crystals.

Furthermore, as described in Japanese Patent Application Laid-Open No.2001-166121, it is commonly employed to provide the cutting mark nearthe intersection between the cutting lines, and such a cutting mark isalso formed in the case of surface close attachment and bezel slimming.However, the cutting mark is primarily provided as the indication of theposition for cutting, and may not particularly affect spreading out ofpaste materials as typically formed by a thin film of a metal, a resinor the like. This means that the cutting mark described in JapanesePatent Application Laid-Open No. 2001-166121 may not solve the aboveproblems.

As described above, there has not been proposed an effective methodwhich may allow manufacturing of liquid crystal display devices with asufficiently slim bezel both by surface close attachment and at a highyield ratio.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a technique formanufacturing liquid crystal display devices with a slim bezeleffectively at a high yield ratio by using surface close attachment.

A liquid crystal display device according to the present inventionincludes: a first substrate; a second substrate disposed at a positionfacing the first substrate; a transfer member provided at a cornerportion in a bezel region of the first substrate and the secondsubstrate; a spacer member for maintaining a distance between the firstsubstrate and the second substrate within a predetermined range; and acutting mark made of the same material as that of the spacer member, anddisposed on the first substrate between a cutting line for the firstsubstrate from a mother substrate and the transfer member.

According to the present invention, the cutting mark is made of the samematerial as that of the spacer member for maintaining the distancebetween the first substrate and the second substrate within apredetermined range, and formed between the cutting line and thetransfer member on the first substrate, and accordingly provides afunction as an indication for a position for cutting, as well as afunction to prevent the transfer member from being spread out. Further,as the cutting mark holds a portion between the corner portion on abezel region of first substrate and the cutting line, it is possible toprovide stable cutting.

Providing the cutting mark having all of these functions eliminatesnecessity of increasing the number of the formation steps and increasingspace for the corner portion on the bezel region of the first substrate,it is possible to manufacture the liquid crystal display device with aslim bezel more efficiently at a high yield ratio using surface closeattachment.

These and other objects, features, aspects and advantages of the presentinvention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating one example of cutting marks in aliquid crystal display device according to a preferred embodiment;

FIG. 2 is a diagram illustrating another example of the cutting marks;

FIG. 3 is a diagram illustrating one example of a cutting assistpattern;

FIG. 4 is a diagram illustrating another example of the cutting assistpattern;

FIG. 5 is a plan view illustrating a liquid crystal panel of the liquidcrystal display device;

FIG. 6 is a sectional view taken along line VI-VI in FIG. 5;

FIG. 7 is an enlarged view of a portion indicated by VII circled by analternate long and short dash line in FIG. 5;

FIG. 8 is a flowchart showing steps for assembling the liquid crystalpanel; and

FIG. 9 is a diagram illustrating a layered structure of the cuttingassist pattern.

DESCRIPTION OF THE PREFERRED EMBODIMENT Preferred Embodiment

Hereinafter, a preferred embodiment of the present invention will bedescribed with reference to the drawings. FIG. 1 is a diagramillustrating one example of cutting marks 1 in a liquid crystal displaydevice according to the preferred embodiment. The figure is onlyschematically provided, and may not reflect an accurate size ofillustrated components or the like. Further, for the sake of simplicity,a configuration other than major part of the present is omitted orpartially simplified as needed. This also applies to the remainingfigures. Moreover, throughout the drawings, like components illustratedin preceding figures are denoted by like reference numerals, anddescriptions for such components shall be omitted when appropriate.

The liquid crystal display device is provided with, as a liquid crystalpanel constituting the device, a TFT (Thin Film Transistor) liquidcrystal panel of a dual-directional display type. FIG. 1 shows a mothercolor filter substrate (hereinafter referred to as “mother CFsubstrate”) 19 in a manufacturing process of the liquid crystal panelbefore cutting, and a characteristic configuration of the presentinvention will be described with reference to FIG. 1.

The liquid crystal panel of the liquid crystal display device isprovided with a color filter substrate (hereinafter referred to as “CFsubstrate”) 9 as a first substrate, a switching device substrate(hereinafter referred to as “TFT substrate”) 8 as a second substrate(see FIG. 6), the cutting marks 1, transfer members 3, and a sealpattern 4 (sealing member). In FIG. 1, illustration of the TFT substrate8 is omitted, and details of this component will be described later.

The CF substrate 9 is one of substrates into which a mother CF substrate19 (mother substrate) is separated, and cutting lines 2 are shown in themother CF substrate 19. The cutting lines 2 are lines for cutting andseparating the mother CF substrate 19 into the plurality of the CFsubstrates 9, and correspond to sides of the CF substrates 9. Thetransfer member 3 is formed, for example, by a resin in whichelectrically-conductive particles are mixed, and applied to (formed at)each corner of a bezel region 31 (see FIG. 6) of the CF substrate 9 andthe TFT substrate 8. The seal pattern 4 is formed by a sealing member,at a region enclosing a display region 30 (see FIG. 6) of the CFsubstrate 9 and the TFT substrate 8.

The cutting mark 1 is formed between the cutting lines 2 and thetransfer member 3 on the CF substrate 9. More specifically, the cuttingmark 1 is formed in an L-shape at a region around an intersectionbetween the cutting lines 2 so as to cut in between an applied portionof the transfer member 3 and the cutting lines 2. A cornered portion ofthe cutting mark 1 is positioned at a corner of the CF substrate 9. Thecutting mark 1 is formed by the same material as that of columnarspacers 63 (more specifically, by an organic resin film) (see FIG. 6)that will be later described. In FIG. 1, the four CF substrates 9 andthe four cutting marks 1 are shown.

The cutting lines 2 are pseudo lines, and practically not shown on themother CF substrate 19. Each pair of the four cutting marks 1 ispositioned in a line-symmetric manner vertically or horizontally in FIG.1, and vertical and horizontal symmetry axes correspond to the cuttinglines 2. Accordingly, the cutting lines 2 are considered to bepositioned between the four cutting marks 1, and the substrate is cuttaking the symmetry axes of the four cutting marks 1 as an indication.In other words, the cutting marks 1 serve as an indication for cutting.

Further, while details will be described later, a scribe lineconstituting a starting point for cutting is provided along each cuttingline 2. The cutting marks 1 are provided on both sides of the scribeline, and can hold the CF substrate 9 from a back surface around thescribe line, and a force from teeth of a scribe wheel may be fullytransferred to a front surface of the CF substrate 9. As a result, it ispossible to achieve a depth of a groove of the scribe line that allowsstable cutting. In other words, the cutting marks 1 also serve as acutting assist pattern that allows stable cutting. In particular, as thecorner portions are susceptible to wrong cutting such as cracking andchipping due to the cutting, an effect of capability of stabilizing thecutting by the provision of the cutting marks 1 is noticeable.

Moreover, by providing the cutting marks 1, the transfer members 3 thathave been spread when applied and bonded are blocked by the cuttingmarks 1, and therefore may not be spread over the cutting line 2.Therefore, it is possible to obtain a liquid crystal display devicewithout causing wrong cutting, such as cracking and chipping, due to thecutting caused by adhesion (bonding) between the TFT substrate 8 and theCF substrate 9 by the transfer members 3 at a region along the cuttinglines 2 or over the cutting lines 2.

Next, another example of the cutting marks 1 will be described. FIG. 2is a diagram illustrating another example of the cutting marks 1.Referring to FIG. 2, each cutting mark 1 is formed so as to enclose thetransfer member 3. More specifically, the cutting mark 1 is slightlymodified such that the L-shape in FIG. 1 is provided with extensions(with additional walls in other directions than toward edges of thesubstrate with respect to the transfer member 3), so as to be able tofurther enclose the transfer member 3 as compared to that of theL-shape.

With this configuration, it is possible to prevent the transfer member 3from being spread in other directions than toward the edges of thesubstrate as well. In other words, it is possible to more effectivelyprevent the transfer member 3 from being spread while still allowing theroughly L-shaped indication to function as the cutting assist patternuseful for forming the scribe line.

Next, a case in which a cutting assist pattern 5 is provided will bedescribed. FIG. 3 is a diagram illustrating one example of the cuttingassist pattern 5. Referring to FIG. 3, on the CF substrate 9, inaddition to the L-shaped cutting marks 1, the cutting assist pattern 5is provided at a predetermined distance from the cutting marks 1.Similarly to the cutting marks 1, the cutting assist pattern 5 is madeof the same material as that of the columnar spacers 63 (morespecifically, by an organic resin film). The cutting assist pattern 5 isformed in a shape of a dashed line along the cutting line 2, wheresections of the pattern are positioned at predetermined intervals.Further, the cutting assist pattern 5 is provided along the cutting line2 at a position closer to the cutting line 2 as compared to the sealpattern 4, and more specifically, at a position along the line apartfrom the cutting line 2 by a predetermined distance set within a rangefrom 40 μm to 100 μm.

It should be noted that the cutting assist pattern 5 is not limited tothe shape of the dashed line, and may be provided in a shape of acontinuous straight line along the cutting line 2. However, if acompletely closed space is formed in a plane pattern between the sealpattern 4 and the cutting assist pattern 5, a pressure differencetypically occurs between an exterior and interior of the closed space ina transition between a vacuum state and a state in atmospheric pressurewhen injecting liquid crystals in manufacturing. This may result in alocally adverse effect to a gap between the TFT substrate 8 and the CFsubstrate 9 (gap between the substrates). Therefore, it is preferablethat the cutting assist pattern 5 be provided with an opening at least apart of the pattern, including such an example in which the pattern isformed in the shape of the dashed line as in this preferred embodiment.

The seal pattern 4 is divided in two at the corner portion of the bezelregion 31 of the CF substrate 9 and the TFT substrate 8, and includes aprotrusion 4 a protruding rightward in FIG. 3 and a protrusion 4 bprotruding rightward from the lower part in FIG. 3. A tip end of theprotrusion 4 a is in contact with the cutting mark 1, and a tip end ofthe protrusion 4 b is in contact with the cutting assist pattern 5adjacent to the cutting mark 1. Between the protrusions 4 a and 4 b at apredetermined interval, an inlet 6 for liquid crystals is defined.Therefore, the cutting mark 1 and the cutting assist pattern 5 adjacentto the cutting mark 1 can prevent the protrusions 4 a and 4 b fromspreading out to the cutting line 2, and thus a liquid crystal displaydevice may be obtained without causing wrong cutting such as crackingand chipping due to the cutting.

The cutting mark 1 is provided so as to continue to a different one ofthe cutting marks 1 provided for a different one of the CF substrates 9of the mother CF substrate 19 adjacent across the cutting line 2 in adirection in which the protrusion 4 a protrudes. The cutting assistpattern 5 adjacent to the cutting mark 1 is provided so as to continueto a different one of the cutting assist patterns 5 provided for thedifferent one of the CF substrates 9. Specifically, a gap between aportion at which the adjacent cutting marks 1 are connected and aportion at which the adjacent cutting assist patterns 5 are connected iscommunicated with the inlet 6.

Further, the protrusions 4 a and 4 b do not serve as a guide for liquidcrystals into the inlet 6 when injecting liquid crystals, as notreaching the edge of the substrate. Therefore, in this preferredembodiment, along with the protrusions 4 a and 4 b, the portion at whichthe adjacent cutting marks 1 are connected and the portion at which theadjacent cutting assist patterns 5 are connected serve as the guide forliquid crystals to be injected within the inlet 6.

Moreover, similarly to the cutting marks 1 shown in FIG. 1, the cuttingmarks 1 and the cutting assist patterns 5 are provided on both sides ofthe scribe line, and hold the CF substrate 9 from the back surfacearound the scribe line. Therefore, with the cutting marks 1 and thecutting assist patterns 5, a force from the teeth of the scribe wheelmay be fully transferred to the front surface of the CF substrate 9, andit is possible to achieve a depth of the groove of the scribe line thatallows stable cutting. In other words, the cutting marks 1 and thecutting assist patterns 5 also serve to prevent the protrusions 4 a and4 b from being spread out, provide an indication for the position forcutting, and allow stable cutting. It should be noted that while notshown in FIG. 3, the transfer members 3 may be provided similarly to thecases of FIG. 1 and FIG. 2.

Next, another example of the cutting assist patterns 5 will bedescribed. FIG. 4 is a diagram illustrating another example of thecutting assist patterns 5. Referring to FIG. 4, portions of the cuttingmarks 1 and the cutting assist patterns 5 that cross the cutting line 2,that is, the portion at which the adjacent cutting marks 1 are connectedand the portion at which the adjacent cutting assist patterns 5 areconnected are formed more thinly than the remaining portions of thecutting marks 1 and the cutting assist patterns 5. Accordingly, theconnected portions may not disturb the cutting and the substrates areless susceptible to cracking. It should be noted that while not shown inFIG. 4, the transfer members 3 may be provided similarly to the cases ofFIG. 1 and FIG. 2.

Next, a specific configuration and a manufacturing method of the liquidcrystal display device will be described more in detail. First, aconfiguration of a liquid crystal panel 20 that constitutes the liquidcrystal display device will be described with reference to FIG. 5through FIG. 7. FIG. 5 is a plan view illustrating the liquid crystalpanel 20 of the liquid crystal display device, FIG. 6 is a sectionalview taken along line VI-VI in FIG. 5, and FIG. 7 is an enlarged view ofa portion indicated by VII circled by an alternate long and short dashline in FIG. 5.

Referring to FIG. 5, the liquid crystal panel 20 is provided with theTFT substrate 8, the CF substrate 9, and the seal pattern 4. On the TFTsubstrate 8, TFTs as switching devices are arranged in an array, and acolor filter and the like are provided on the CF substrate 9.

The seal pattern 4 is provided for the bezel region 31 so as to encloseat least the display region 30 between the TFT substrate 8 and the CFsubstrate 9, and seals the gap between the CF substrate 9 and the TFTsubstrate 8. The display region 30 is a region corresponding to adisplay screen in which an image is displayed when the liquid crystalpanel 20 is operated. It should be noted that as the display region 30and the bezel region 31, the region on the TFT substrate 8, the regionon the CF substrate 9, and the region between the substrates 8 and 9 arewholly used, and the same is true throughout this description.

Between the TFT substrate 8 and the CF substrate 9, there are provided,within the display region 30, a large number of the columnar spacers 63(spacer members) for forming and maintaining a gap of a certain rangebetween the substrates 8 and 9, in other words, for maintaining adistance between the substrates 8 and 9 within a certain range. Further,as described above, the columnar spacers 63 are made of organic resinfilms, and the cutting assist patterns 5 and the cutting marks 1 on thebezel region 31 are also made of the same material as that of thecolumnar spacers 63. The cutting assist pattern 5 is formed in the shapeof a dashed line along the edge of the CF substrate 9, that is, thecutting line, and the cutting marks 1 are provided at the cornerportions of the substrate.

Moreover, as described above, during manufacturing, a differentsubstrate adjacent to the CF substrate 9 across the cutting line on thefirst mother substrate is also provided with the cutting assist pattern5 and the cutting marks 1. However, in FIG. 5 and FIG. 6, the cuttingassist pattern 5 and the cutting marks 1 that are provided for theadjacent different liquid crystal panel or for small scraps of thesubstrate to be cut and removed are not shown as not constituting theliquid crystal panel 20.

A liquid crystal layer is formed by liquid crystals 70 (a liquid crystalmaterial) sealed by the seal pattern 4 and sandwiched at least in thedisplay region 30 within a gap between the CF substrate 9 and the TFTsubstrate 8 held by the columnar spacers 63. In addition, the sealpattern 4 is provided with the inlet 6 which is an opening for injectingthe liquid crystals 70, and the inlet 6 is sealed by a sealing member 62from outside the liquid crystal panel 20. In other words, the liquidcrystal material is sealed within a region enclosed by the seal pattern4. In this case, a TN (Twisted Nematic) liquid crystal material that iscommon as the liquid crystal material is used.

Further, as described with reference to FIG. 3 and FIG. 4, by bringingthe tip ends of the protrusions 4 a and 4 b of the seal pattern 4 thatdefine the inlet 6 into contact with the cutting mark 1 and the cuttingassist pattern 5 made of the same material as that of the columnarspacer 63, it is possible to prevent the protrusions 4 a and 4 b of theseal pattern 4 from reaching the edge of the substrate. In other words,at the edge of the substrate, the inlet 6, the cutting mark 1, and thecutting assist pattern 5 serve as a guide when injecting the liquidcrystals 70. However, as illustrated in FIG. 7, after injecting theliquid crystals 70, the sealing member 62 is pulled into the protrusions4 a and 4 b of the seal pattern 4, and the inlet 6 is completely sealedby the protrusions 4 a and 4 b of the seal pattern 4 and the sealingmember 62.

Next, the TFT substrate 8 and the CF substrate 9 will be described.

The TFT substrate 8 is provided with a glass substrate 41 formed by atransparent substrate of common glass with a thickness of about 0.7 mm.The TFT substrate 8 is further provided with an oriented film 42 forcausing liquid crystals oriented on one side of the glass substrate 41,pixel electrodes 43 disposed under the oriented film 42 and configuredto apply voltages for driving the liquid crystals, TFTs 44 as switchingdevices for supplying voltages to the pixel electrodes 43, an insulatorfilm 45 covering the TFTs 44, a plurality of gate lines 46 and sourcelines 47 as lines for supplying signals to the TFTs 44, a signalterminal 48 for receiving signals supplied to the TFTs 44 from outside,transfer electrodes (not shown) for transmitting signals inputtedthrough the signal terminal 48 to a common electrode 53, and the like.In addition, a polarizer plate 64 is disposed on the other side of theglass substrate 41.

The CF substrate 9 is provided with a glass substrate 51 formed by atransparent substrate of extremely-thin glass with a thickness of about0.1 mm. The CF substrate 9 is further provided with an oriented film 52for causing liquid crystals oriented on one side of the glass substrate51, the common electrode 53 disposed above the oriented film 52 andconfigured to generate an electric field with the pixel electrodes 43 onthe TFT substrate 8 to drive the liquid crystals, a black matrix (BlackMatrix, or BM) 55 as a light shielding layer for shielding between colorfilters 54 disposed on the common electrode 53 or for shielding light tothe bezel region 31 disposed outside a region corresponding to thedisplay region 30, and the like. On the other side of the glasssubstrate 51, as a dual-directional display, a parallax barrier 56 isdisposed which serves as a light shielding layer that divides the viewinto two directions. The parallax barrier 56 includes a slit opening ata position displaced from an opening of the BM 55 disposed within pixelsto divide and limit the viewing directions. In addition, a polarizerplate 65 is disposed at the side outer than (above) the parallax barrier56.

The color filters 54 are configured to serve as a filter thatselectively transmits light in a specific range of wavelength such asred, green, or blue, by selecting a color material layer in whichpigments are dispersed in a resin such that color material layers ofdifferent colors are arranged with regularity. In FIG. 5 and FIG. 6, thecolor filters 54 are shown as color filters of red, green, and blue,respectively. The BM 55 is also disposed on the bezel region 31 outsidethe display region 30, in addition to a region between the color filters54. Specifically, the BM 55 is disposed substantially over an entireregion of the bezel region 31 on the CF substrate 9, and shields lightat the bezel region 31 in the CF substrate 9 unnecessary for display.

As the light shielding layer configured by the BM 55 and the parallaxbarrier 56, a material such as a metallic material using a film stack ofchrome and chromic oxide, or a resin-based material in which blackparticles are dispersed in a resin may be selected. Note that anover-coating layer made of a transparent resin film may be providedbelow the oriented film 52, so as to cover the color filters 54 and theBM 55.

Further, the TFT substrate 8 and the CF substrate 9 are bonded togetherby the seal pattern 4, and held with a predetermined gap between thesubstrates by the columnar spacers 63 disposed in the display region 30.In addition, the transfer electrode and the common electrode 53 areelectrically connected by the transfer member 3, through which a signalinputted from the signal terminal 48 is transmitted to the commonelectrode 53. The transfer member 3 is illustrated at each cornerportion at right top and bottom in FIG. 5, and as described withreference to FIG. 1 and FIG. 2, disposed close to the inner side of theL-shaped cutting mark 1 made of the same material as that of thecolumnar spacers 63 such that the cutting mark 1 prevents the transfermember 3 from being spread toward the edge of the substrate more thanrequired.

Moreover, the liquid crystal panel 20 is provided with a control board66 for generating a drive signal, a FFC (Flexible Flat Cable) 67 thatelectrically connects the control board 66 with the signal terminal 48,a backlight unit as a light source (not shown here, while normallydisposed to face a side of the TFT substrate 8 opposite from the CFsubstrate 9 side constituting the display screen), and the like. Alongwith these components, an outer portion of the CF substrate 9 in thedisplay region 30 constituting the display screen is housed in an opencasing (not shown), thereby constituting the liquid crystal displaydevice.

The liquid crystal panel 20 that constitutes the liquid crystal displaydevice described above is operated in the following manner. For example,upon input of an electrical signal from the control board 66, a drivevoltage is applied to the pixel electrode 43 and the common electrode53, and orientation of molecules of the liquid crystals 70 in the liquidcrystal layer changes in accordance with the drive voltage. Then, bytransmitting or blocking light emitted from the backlight unit to a sideof a viewer through or by the TFT substrate 8, the liquid crystals 70,and the CF substrate 9, a video image or such is displayed in thedisplay region 30 of the liquid crystal panel 20.

As the liquid crystal panel 20 that constitutes the liquid crystaldisplay device is a dual-directional liquid crystal display panel, theparallax barrier 56 limits light transmitted through the CF substrate 9to ranges of predetermined viewing angles in two directions.Specifically, the video image or such is displayed with effective rangesof viewing angles in two directions with respect to the display screen,toward left top and right top in FIG. 6. In addition, the liquid crystaldisplay device serves as the dual-directional liquid crystal displaypanel in such a manner that display pixels are set for the liquidcrystal display device corresponding to the effective ranges of viewingangles in two directions, and different video images are displayed forthe effective ranges of viewing angles in two directions by performingdifferent video display. As display features, the dual-directionalliquid crystal display panel in particular using extremely-thin glass issuperior in that a pixel pitch may be set small and the effective rangesof viewing angles in two directions may be more separately.Specifically, it is possible to be advantageously utilized in a case inwhich different high-resolution video images are displayed respectivelyfor a plurality of viewers in the driver seat and the passenger seat ina car, for example.

Further, although the liquid crystal display device according to thispreferred embodiment is a dual-directional liquid crystal display panelusing extremely-thin glass that is susceptible to wrong cutting and withwhich it is difficult to provide a high yield ratio in manufacturing, itis possible to manufacture the liquid crystal display device accordingto this preferred embodiment at a high yield ratio as havingcharacteristic configurations near the corner portions and the edge ofthe substrate of the liquid crystal panel 20.

As the above effects may be achieved significantly when the presentinvention is applied to a liquid crystal panel using extremely-thinglass, it is also possible to achieve the same effect with a curvedliquid crystal display having a curved display screen usingextremely-thin glass as well. In addition, while slightly less effectivein the improvement of a yield ratio, it is possible to obtain the effectof the present invention in the reduction of wrong cutting for a normalliquid crystal display device not using extremely-thin glass, and thecutting marks 1 and the cutting assist patterns 5 of the presentinvention may be applied to such liquid crystal display devices.

Next, a method of manufacturing the liquid crystal panel 20 thatconstitutes the liquid crystal display device according to the preferredembodiment will be described. Here, an outline of steps for assemblingthe liquid crystal panel 20 will be described with reference to aflowchart shown in FIG. 8. FIG. 8 is a flowchart showing the steps forassembling the liquid crystal panel 20.

First, in a substrate preparation step, a mother TFT substrate (notshown) for obtaining the TFT substrate 8 and the mother CF substrate 19for obtaining the CF substrate 9 before bonded together are prepared(Step S1). While the CF substrate 9 is ultimately processed toextremely-thin glass by thinning process, a mother TFT substrate and themother CF substrate 19 made of glass of thickness ranging from 0.5 mm to1.5 mm are used in the process of the manufacturing steps before thethinning process in order to facilitate the following steps. Here, boththe mother TFT substrate and the mother CF substrate 19 are prepared assubstrates made of glass of thickness 0.7 mm.

A method of manufacturing the mother TFT substrate and the mother CFsubstrate 19 will be described only simply, as a common manufacturingmethod may be employed. First, the mother TFT substrate is manufacturedby forming the TFTs 44 and the pixel electrodes 43, a line layerincluding the gate lines 46 and the source lines 47, the signal terminal48, and the transfer electrode on the one side of the glass substrate 41using a known manufacturing method, for example, by repeating a filmformation and a pattern formation step such as patterning and etchingbased on the photolithographic approach.

Similarly, the mother CF substrate 19 is manufactured using a knownmanufacturing method, by forming the color filters 54, the BM 55, andthe common electrode 53 on the one side of the glass substrate 51 byrepeating a film formation step to the pattern formation step and thenforming the columnar spacers 63 by patterning an organic resin film, forexample. The cutting marks 1 and the cutting assist patterns 5 made ofthe same material as that of the columnar spacer 63, which are thecharacteristic configuration of the present invention, are formed at thesame time as the columnar spacers 63, and only a change in a patterndesign such as a plane arrangement needs to be made to the normal methodof forming the columnar spacer 63. In other words, the method itself offorming the columnar spacers 63 may be common and known, and the motherCF substrate 19 may be manufactured employing a method within knownmanufacturing methods.

Then, in a substrate cleaning step, the mother TFT substrate thusprepared is cleaned (Step S2). Next, in an oriented film materialapplication step, an oriented film material is applied and formed on oneside of the mother TFT substrate (Step S3). In this step, for example,the oriented film material made of an organic film is applied using aprinting method and dried by a baking treatment using a hot plate andsuch. Then, in a rubbing step, the oriented film material is subjectedto rubbing and an alignment treatment is performed to a surface of theoriented film material, and thus the oriented film 42 is formed (StepS4).

Similarly to the Steps S2 to S4, on the mother CF substrate 19, theoriented film 52 is formed by cleaning, application of the oriented filmmaterial, and rubbing.

Subsequently, in a sealing member application step, using a screenprinting machine, the sealing member in the form of a printing paste isapplied to one side of the mother TFT substrate or the mother CFsubstrate 19, and the seal pattern 4 for ultimately enclosing thedisplay region 30 is formed. Then, in a transfer member applicationstep, the transfer member 3 in the form of a paste material made of aresin in which electrically-conductive particles are mixed is appliedthrough a syringe nozzle and such to the one side of the mother TFTsubstrate or the mother CF substrate 19 (Step S5).

Thereafter, in a bonding attachment step, a cell substrate is formed bybonding the mother TFT substrate and the mother CF substrate 19 together(Step S6). At this time, the seal pattern 4 is sandwiched between themother TFT substrate and the mother CF substrate 19, and a region forforming the sealing member in the form of a paste spreads. However, inthe preferred embodiment, the cutting assist pattern 5 in a shape of adashed line is provided between a position to be an edge of thesubstrate after separation in a subsequent step, i.e., between aposition of the cutting line 2 and the region for forming the sealpattern 4, and in addition the cutting mark 1 and the cutting assistpattern 5 are provided between a position of the protrusions 4 a and 4 bof the seal pattern 4 forming the inlet 6 and the position of thecutting line 2. Therefore, it is possible to prevent infiltration of thesealing member caused by being spread on the position of the cuttingline 2, or to an adjacent liquid crystal panel region across the cuttingline 2.

Similarly, while the transfer member 3 in the form of a paste issandwiched and spread between the mother TFT substrate and the mother CFsubstrate 19, in the preferred embodiment, the L-shaped cutting mark 1is provided between the position of the cutting line 2 and the regionfor forming the transfer member 3, it is possible to preventinfiltration of the transfer member 3 caused by being spread on theposition of the cutting line 2 or to the adjacent liquid crystal panelregion across the cutting line 2.

Subsequently, in a sealing member curing step, in a state in which themother TFT substrate and the mother CF substrate 19 are bonded together,the sealing member constituting the seal pattern 4 is completely cured(Step S7). This step is performed in accordance with the material of thesealing member, for example, by heating or ultraviolet irradiation. In acase in which the method of curing the sealing member by heating isselected, the cell substrate may be formed by continuously performingSteps S6 to S7, where the mother TFT substrate and the mother CFsubstrate 19 are bonded together and heated in succession (this processis also referred to as thermocompression bonding).

Then, in order to allow the liquid crystal panel 20 to be curved, or inorder to form dual-directional liquid crystal display panel as in thecase of the preferred embodiment, a polishing/thinning step is performedin which the glass substrate constituting at least one of the mother TFTsubstrate and the mother CF substrate is processed to extremely-thinglass by thinning, in the state where the mother TFT substrate and themother CF substrate are bonded (Step S8).

Specifically, a thinning treatment by a chemical agent or mechanicalpolishing may be selected, and for example, if the chemical thinningtreatment is used, in the case of making both the mother TFT substrateand the mother CF substrate 19 thin, after performing peripheral sealingto a peripheral portion of the mother TFT substrate and the mother CFsubstrate 19 to prevent the chemical agent from coming between thesubstrate and the substrate, the mother TFT substrate and the mother CFsubstrate 19 that have been bonded together as a whole are dipped in thechemical agent to polish surfaces of the mother TFT substrate and themother CF substrate 19 to be made thinner. Further, when only one of theTFT substrate 8 and the CF substrate 9, for example, only the CFsubstrate 9 as in the case of the preferred embodiment is to be thinned,only the surface of the mother CF substrate 19 may be polished andthinned in a state in which a protective layer is formed over thesurface of the mother TFT substrate by resist and such, in addition tothe peripheral sealing.

Then, in a parallax barrier forming step, the parallax barrier 56 madeof a light shielding layer serving as a dual-directional liquid crystaldisplay panel is formed over the surface of the thinned mother CFsubstrate 19 (Step S9). Specifically, a metallic material using a filmstack of chrome and chromic oxide or such depending on the material thatforms the parallax barrier 56 is formed, and a patterning process inaccordance with the material that forms the parallax barrier 56 isperformed into a shape having slit openings at predetermined positionsso as to serve as the parallax barrier 56. The film formation process ofthe metallic material is performed by sputtering together with heatingof the substrates.

Next, in a cell separation step, the mother TFT substrate and the motherCF substrate 19 that have been boned together are separated into a largenumber of individual cells (Step S10). In this step, the large number ofindividual cells may be provided by, using a scribe wheel havingV-shaped teeth, forming a scribe line constituting a starting point forcutting on the surface of the glass substrate 51, and then applying astress to peripheral region of the scribe line for separation.

In the cell separation step, the cutting marks 1 made of the samematerial as that of the columnar spacers 63 serve as indications forspecifying the positions for cutting and the corner portions. Further,both of the cutting marks 1 and the cutting assist patterns 5 are madeof the same material as that of the columnar spacers 63, and are able tohold the CF substrate 9 from back side at the peripheral region on bothsides of the scribe lines when forming the scribe lines.

Therefore, it is possible to appropriately apply the force of the teethof the scribe wheel to the surface of the CF substrate 9 to form ascratch or a groove with a depth suitable for cutting. As a result, itis possible to carry out stable cutting without causing cracking andchipping, by the separation after a scribing step. This effect isnoticeable in particular, when cutting the extremely-thin glass which issusceptible to deflection and not easily applied with a suitable forceby scribing. As for the corner portions, as the seal pattern 4 isnormally formed in a rounded shape (with corners rounded), the cuttinglines 2 are formed relatively distant from the seal pattern 4.Therefore, when forming the scribe lines, the glass substrate is easilydeflected and the force of the teeth of the scribe wheel is not easilytransmitted at these portions. Accordingly, cracking and chipping occurparticularly easily at the corner portion. In contrast, the cuttingmarks 1 provided at the corner portions exert such an effect that, evenat the corner portions where the cutting lines 2 are formed relativelydistant from the seal pattern 4 and the force of the teeth of the scribewheel is not easily transmitted in nature, the cutting marks 1 hold theCF substrate 9 from the back side relatively near the cutting lines 2,and enable stable cutting without causing cracking and chipping. Inother words, an improvement is significant in that the cutting becomesstable even at the corner portions where cracking and chipping occurparticularly easily.

Further, as described above, due to the effect of the cutting marks 1and the cutting assist patterns 5, in the bonding attachment step, it ispossible to prevent infiltration of the paste materials of the sealingmember and the transfer member caused by being spread on the positionsof the cutting lines or to an adjacent liquid crystal panel regionacross the cutting lines. Thus, adjacent liquid crystal panels or smallscraps to be removed may not be adhered (bonded) to the liquid crystalpanel 20 as an object to be cut due to the paste materials of thesealing member and the transfer member, and thus it is possible toprovide stable cutting without causing cracking and chipping of glassdue to spread of the paste materials. The effect of preventing crackingand chipping due to spread of the paste materials may be achievedregardless of the use of extremely-thin glass.

Next, in a liquid crystal injection step, liquid crystals are injectedthrough the inlet of an individual cell (Step S11). This step isperformed, for example, within a vacuum injection device in a vacuumstate, by injecting or filling a liquid crystal material through theinlet by gradually increasing the pressure within the device to theatmosphere pressure while the inlet of the individual cell is broughtinto contact with the liquid crystal material.

Further, in an inlet sealing step, the inlet 6 is sealed (Step S12).This step is performed, for example, by sealing the inlet 6 with a lightcuring resin and irradiating the sealed portion with light. As describedabove, the liquid crystals are injected through a portion of the inlet 6between the cutting mark 1 and the cutting assist pattern 5 that are incontact with the tip ends of the protrusions of the seal pattern 4, withthe cutting mark 1 and the cutting assist pattern 5 as guides. Inaddition, in an inlet sealing step that follows, the sealing isperformed by pulling the sealing member at least into a region betweenthe protrusions of the seal pattern 4.

After separated into individual liquid crystal panels, filled with theliquid crystal material, and sealed in the manner described above, thepolarizer plate 64 and the polarizer plate 65 are respectively appliedto the surfaces of the TFT substrate 8 and the CF substrate 9 outsidethe cell substrate in a polarizer plate application step (Step S13), thecontrol board 66 is mounted in a control board mounting step (Step S14),and then the liquid crystal panel 20 is completed. Subsequently, on theback side of the TFT substrate 8 which is to be non-visible side of theliquid crystal panel 20, a backlight unit is provided using an opticalfilm such as a retarder, the liquid crystal panel 20 and peripheralcomponents are housed appropriately within a frame of a resin or ametal, and thus the liquid crystal display device according to thepreferred embodiment is completed.

In the preferred embodiment, as described above, as a part of theeffects of the present invention is more noticeably achieved when usingextremely-thin glass, the case in which the present invention is appliedto the dual-directional liquid crystal display panel in which only oneof the substrates is made of extremely-thin glass has been described. Asthe noticeable operations and effects described above are commonlyachieved when at least one of the substrates is made of extremely-thinglass, this also applies to curved displays in which both of the TFTsubstrate and the CF substrate are made of extremely-thin glass, andreflective displays in which one of the substrates is made ofextremely-thin glass.

As described above, according to the liquid crystal display device ofthe preferred embodiment, the cutting marks 1 are made of the samematerial as that of the columnar spacers 63 and formed between thecutting lines 2 and the transfer members 3 on the CF substrate 9, andaccordingly provide a function as an indication for cutting positions,as well as a function to prevent the transfer member 3 from being spreadout. Further, as the cutting marks 1 hold the portion between the cornerportions on the bezel region 31 of the CF substrate 9 and the cuttingline 2, it is possible to provide stable cutting.

Providing the cutting marks 1 having all of these functions eliminatesnecessity of increasing the number of the formation steps and increasingspace for the corner portions on the bezel region 31 of the CF substrate9, it is possible to manufacture the liquid crystal display device witha slim bezel more efficiently at a high yield ratio using surface closeattachment. In addition, providing the cutting marks 1 is sufficient forobtaining the above effects, so that the manufacturing may be achievedwith low costs.

As each cutting mark 1 is provided so as to enclose the transfer member3, it is also possible to prevent the transfer member 3 from beingspread in other directions than toward the edges of the substrate.

The liquid crystal display device further includes: the seal pattern 4enclosing the display region 30 between the CF substrate 9 and the TFTsubstrate 8, and the cutting assist patterns 5 disposed on the CFsubstrate 9 along the cutting lines 2 with a predetermined distance fromthe cutting marks 1. The seal pattern 4 is separated so as to have thetwo protrusions 4 a and 4 b constituting the inlet 6 at the cornerportion of the bezel region 31 of the CF substrate 9 and the TFTsubstrate 8, such that tip ends of the two protrusions 4 a and 4 b arebrought into contact respectively with the cutting mark 1 and thecutting assist pattern 5.

Therefore, the cutting assist pattern 5 disposed along the cutting line2 provides a function as an indication for the position for cutting.With the cutting marks 1 and the cutting assist patterns 5 adjacent tothe cutting marks 1, it is possible to prevent the protrusions 4 a and 4b from being spread out to the cutting line 2.

Further, as being made of the same material as that of the columnarspacer 63, the cutting assist pattern 5 holds a region along the cuttinglines 2 which is closer to the cutting lines 2 than to the position ofthe seal pattern 4, and therefore it is possible to provide furtherstable cutting.

The cutting mark 1 and the cutting assist pattern 5 with which the tipends of the two protrusions 4 a and 4 b are brought into contact areconfigured so as to be continuous respectively with the cutting mark 1and the cutting assist pattern 5 provided for a different CF substrate 9that is adjacent across the cutting line 2 in the mother CF substrate 19before cutting, and portions provided across the cutting line 2respectively of the cutting mark 1 and the cutting assist pattern 5 areconfigured more thinly than the remaining portions of the cutting mark 1and the cutting assist pattern 5. Consequently, these portions may notdisturb the cell separation step, and accordingly the substrates areless susceptible to cracking.

Further, at least one of the CF substrate 9 and the TFT substrate 8 ismade of extremely-thin glass. As wrong cutting may not easily occur andmanufacturing at a high yield ratio becomes possible by providing thecutting mark 1 and the cutting assist pattern 5, it is possible tomass-produce dual-directional display devices or curved display devices.

Moreover, in the preferred embodiment, a range of the thickness ofsubstrates regarded as extremely-thin glass typically includes on theorder of 0.1 mm and so described. However, a significant effect may beachieved with a substrate on the order of 0.2 mm, as compared to aliquid crystal display device using a glass substrate whose thickness ison the order of 0.3 mm used in common liquid crystal display devices.Further, a lower limit of this range is 0.01 mm, which is a lower limitof a glass substrate used in common liquid crystal display devices.

Thus, it is possible to achieve the same effect using, not limited toextremely-thin glass whose thickness is on the order of 0.1 mm asexemplified in the preferred embodiment, extremely-thin glass whosethickness is 0.01 mm or more and less than 0.2 mm.

As the cutting marks 1 or the cutting assist patterns 5 are formed atthe same time as the columnar spacers 63, the cutting marks 1 and thecutting assist patterns 5 may be formed easily as it is possible to usea known method of forming the columnar spacers 63 that is commonly used.

It should be noted that the cutting mark 1 and the cutting assistpattern 5 with which the tip ends of the two protrusions 4 a and 4 b arebrought into contact may be formed to have the same layered structure asthat of the columnar spacers 63. This will be described with referenceto FIG. 9. FIG. 9 is a diagram illustrating a layered structure of thecutting assist pattern 5.

Specifically, the columnar spacers 63 disposed on the display region 30are typically provided for portions as light shielding regions where thegate lines on the TFT substrate 8 and the BM 55 on the CF substrate 9overlap, and the cutting marks 1 and the cutting assist patterns 5 aremade to have generally the same layered structure as that of thecolumnar spacers 63 disposed on the display region 30, by providingdummy patterns serving as a base for gap adjustment including a gatelayer dummy pattern 10 made of the same material as that of and at thesame time as the gate lines, a BM dummy pattern 12 made of the samematerial as that of and at the same time as the BM 55, and a colormaterial dummy pattern 11 made of the same material as that of and atthe same time as the color material layer (the color filter 54).

With this, it is possible to make a gap between the substrates 8 and 9for the display region 30, a gap between the substrates 8 and 9 for thecutting marks 1, and a gap between the substrates 8 and 9 for thecutting assist pattern 5 substantially equal, and thus the gap betweenthe TFT substrate 8 and the CF substrate 9 becomes substantiallyidentical with the height of the cutting mark 1 and the cutting assistpattern 5. Accordingly, the cutting mark 1 and the cutting assistpattern 5 are brought into contact with and generally closely attachedto the surfaces of the substrates 8 and 9. As a result, it is possibleto prevent air from intruding when injecting liquid crystals, thus toprovide more stable injection of liquid crystals.

While the invention has been shown and described in detail, theforegoing description is in all aspects illustrative and notrestrictive. It is therefore understood that numerous modifications andvariations can be devised without departing from the scope of theinvention.

What is claimed is:
 1. A liquid crystal display device, comprising: afirst substrate; a second substrate disposed at a position facing saidfirst substrate; a transfer member provided at a corner portion in abezel region of said first substrate and said second substrate; a spacermember for maintaining a distance between said first substrate and saidsecond substrate within a predetermined range; and a cutting mark madeof the same material as that of said spacer member, disposed on saidfirst substrate between a cutting line for the first substrate from amother substrate and said transfer member, and holding said firstsubstrate from a back surface side around a scribe line when said scribeline is provided to cut said first substrate from said mother substrate,wherein a sealing member encloses a display region between said firstsubstrate and said second substrate, said transfer member is provided ata spaced distance apart from said sealing member, and said transfermember is provided between said sealing member and said cutting line,said transfer member connects a common electrode and a transferelectrode positioned outside the sealing member, and said cutting markhas an open part to open a part in which the transfer member faces thesealing member.
 2. The liquid crystal display device according to claim1, wherein said cutting mark is provided so as to enclose said transfermember.
 3. The liquid crystal display device according to claim 1,wherein said cutting mark is configured by the same layered structure asthat of said spacer member and has the same height as that of saidspacer member, and said layered structure comprises a plurality ofdifferent layers.
 4. The liquid crystal display device according toclaim 1, wherein at least one of said first substrate and said secondsubstrate is made of extremely-thin glass.